Disclosed is a method and computer-readable medium for bit and power allocation for modems sharing a common multi-carrier binder, including Discrete Multi-Tone (DMT) based Digital Subscriber Line (DSL) modems. In one preferred embodiment, the method includes the steps of initializing a modem by calculating loop-to-loop channel transfer functions and noise power spectral densities (PSDs) at a corresponding receiver, and taking into account cross-talk between loops in the process of allocation so as to maximize total data rates within the binder.
Legal claims defining the scope of protection, as filed with the USPTO.
1. A method suitable for use in allocating information bits and power among user modems and frequency bins in a multi-carrier binder, said method comprising: calculating a set of incremental power values for increases in bit count for a set of all frequency bins in a multi-carrier binder; determining a least incremental power value in the set of incremental power values; identifying as a least-incremental-power-bit frequency bin a frequency bin having the least incremental power value, the least-incremental-power-bit frequency bin having a corresponding bit count, the least-incremental-power-bit frequency bin corresponding to a selected user; increasing the bit count in the least-incremental-power-bit frequency bin in response to identifying, wherein the increasing the bit count includes setting a flag indicating a full frequency bin when the increased bit count exceeds a pre-established maximum bit-count value; calculating power values for other non-selected users within the multi-carrier binder in response to increasing the bit count; and repeating the increasing, including the setting a flag, and calculating power values for other non-selected users until a predefined criterion has been satisfied.
2. The method of claim 1 , wherein a first predefined criterion corresponding to the least-incremental-power-bit frequency bin comprises having an incremental power requirement for an increase in bit-count which is less than or equal to an incremental power requirement for an increase in bit-count for another frequency bin in the multi-carrier binder.
3. The method of claim 1 , wherein the bit-count comprises an initial predetermined number of bits.
4. The method of claim 1 , wherein the increasing the bit-count comprises increasing the bit-count by one bit.
5. The method of claim 1 , wherein a second predefined criterion is satisfied if power allocated to the least-incremental-power-bit frequency bin meets or exceeds a pre-established power value.
6. The method of claim 1 , wherein the power values are substantially equivalent to minimum power values required by the non-selected users to offset increased cross-talk resulting from the increasing the bit count.
7. The method of claim 1 , wherein the identifying a frequency bin comprises calculating a weighted power sum, the weighted power sum being a function of weight factors and incremental power values for frequency bins in the multi-carrier binder.
8. The method of claim 7 , wherein the weighted power sum is further a function of noise and signal-to-noise ratio in a corresponding frequency bin.
9. The method of claim 1 , further comprising measuring channel matrix parameters and noise in the frequency bins prior to the identifying the least-incremental-power-bit frequency bin.
Cooperative Patent Classification codes for this invention. Click any code to explore related patents in that topic.
September 4, 2008
November 24, 2009
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